Device for eliminating static current and for tuning radio receiving sets



May 8, 1928. 1,669,171

J. 5. PALMER DEVICE FOR ELIMINATING STATIC CURRENT AND FDR TUNING RADIO RECEIVING SETS Filed on. 15. 1924 larly pointed out in the following-detailed Patented May 8, 1928.

UNITED STATES PATENT OFFICE.

JEFFERSON S. PALMER, OF FARMINGTOIN, NEW MEXICO.

SETS.

DEVICE FOR ELIMINATING STATIC CURRENT AND FOR TUNING RADIO RECEIVING Application filed October 15, 1924. Serial No. 743,7i9.

This invention relates to devices for use in connection with radio receiving sets, particularly for tuning the input circuit of said receiving set, and for eliminating static interference therein.

An object of the invention resides in providing a device adapted for connection in the circuit between the antenna and the receiving set, as well as-the ground and the receiving set, which includes a pair of relatively adjustable elements, adapted for tuning the input circuit, and another pair of elements relatively adjustable, and having an inductive relation with one another, so that static current may be induced to flow between the last mentioned elements, in order that theymay be conducted from the antenna circuit to the ground circuit, without passing through the radio receiving set, and which thereby eliminates said static current from the set..

Another object of the'invention resides in providing a-splder web inductance having one'free end connected with the antenna, and

' with which is associated a movable plate member adapted for adjustment axially relative to said spider web inductance, and which supports in spaced relation-thereto a movable inductance coil arranged in the magnetic field of an electromagnet, the inductance coil being electrically connected with the plate, and one side of the input circuit of a receiving set, so that in the antenna circuit the current flows from the antenna through the spider web inductance and then to the plate, and movable inductance coil before enteringthe set, while the ground circuit of said receiving set is through a variable condenser and theelectromagnet, before reaching the ground, from Which it will be understood that static current will be conducteddirectly from the antenna to the ground, by the inductive relation of the movable induc tance coil, andthe electromagnet, in order that such currents, which set up undesirable noises in the receiving set may be eliminated.

The invention also includes other objects and improvements in the details of construction and arrangement oftpartsfor carrying out the invention, which are more particudescription, and' in the claims directed to a preferred form of the invention, it being understood, however, that various changes in the minor details and manner of construction may be made, without departing from the spirit and scope of the and claimed.

The figure illustrates a partial" diagram matic and structural View of the improved device, showing the wiring connections with the input circuit of. the radio set, together with the ground and antenna connections,

invention as described the supports for the several elements of the device being omitted for the sake of clear- .sides of the plate member connect the same with the supporting-member 6 of a primary inductance coil 7, having the windings 8 wound on said supporting member, one end. of said winding being connected by a wire 9 to one of the rods5establishing electrical connection between the coil 8 and plate member 4. A rack bar 10 is mounted on said plate 4 and the teeth 11 thereon engage the toothed periphery of a pinion 12, mounted, on the shaft 13 and adapted to be manually rotated through the operation of the knob 14, in order thatthe disc 4 and the inductancc coil 7 may be moved for changing the relative position'of the plate at with respect to the spider web inductance l and the position of the movable inductance coil 7 with respcct'to the stationary electromagnet 15.

The stationary electromagnet includes a laminated core 16 and coil winding 17 one end of the coil winding and the core being electrically connected to the ino round 18 through v wire connections 19. he wire connection 20 electrically connects the opposite end of the core 16 with the connection 19 so that both ends of the core 16 are through a wire connection 23, while the other terminal 24 of the radio receiving set is connected to the free end of the coil windings 8 of the movable inductance coil, through a wire connection 25, in which is interposed a controlling switch 26.

The bar member 27 carries an adjustable screw member 28, which is arranged to adjust the air gap with the upturned end 29 of the parallel bar member 30 arranged in parallel spaced relation to the bar member 27, which bar members are electrically connected by wire members 31 and 32 respective: ly, with the wires 19 and 25 respectively, so that a by-pass circuit containing an adjustable air gap having a predetermined resistance is connected across the antenna ground circuit for diverting the static to the ground.

With the parts connected as above described, it will be seen that the operation of the knob or handle 14 will effect an adjustment of the movable inductance coil 7 and the plate 4 relative to the stationary magnet and the spider web inductance 1, which will efiect a tuning of the input circuit of the receiving set according to the spacing of the plate 4, relative to the spider web inductance 1. At the same time, the relative adjustment of the movable inductance coil with respect to the stationaryelectromagnet will effect the inductive relationbetween said magnet and inductance coil, in such a manner that static electricity andundersirable received currents will be transmitted by induction to the core 16 of the electromagnet and then to the ground, and not into the input circuit of the receiving set.

It will thus be seen that a novel and simple device has been provided for eliminating static interference in the input circuit of a radio receiving set, and at the same time providing an additional tuning device for tuning an incoming signal.

What is claimed is:

,1. A device of the class described comprising a stationary inductance coil, 3. plate movably mounted in the magnetic field of said inductance coil, a stationary electromagnet mounted in spaced relation to said inductance, a movable inductance coil mounted in spaced relation to said plate and in inductive relation to the electromagnet, and connections for interposing the stationary inductance coil, plate and movable inductance coil in the circuit between the antenna and the input circuit of a radio receiving set, and for interposing the electromagnet in the circuit connecting said receiving set with the ground.

2. A device of the class described comprising a stationary inductance coil, a plate mounted in the field of said coil and axially movable therein, a. movable inductance coil connected with said plate and arranged in spaced relation thereto, a stationary electromagnet mounted ad]acent said movable inductance coil and arranged in inductive relation thereto, means for adjusting said plate and movable inductance coil, and connections for .interposing the stationary inductance coil, the plate, and the movable inductance coil in the circuit between the antenna and one side of the input circuit of the radio receiving set, and connections between the other side of the input circuit and the radio receiving set and the ground, for interposing the stationary electromagnet in said circuit.

3. A device of the class described comprising a stationary inductance coil connected with an antenna, a stationary electroinagnet connected between the ground and one side of the input circuit of a radio receiving set, and means arranged in inductive relation with said stationary inductance coil and said electromagnet, electrically connected with the other side of the input circuit of said receiving set, and relatively adjustable to said stationary coil, said clcctromagnet tuning said input circuit of the ra dio receiving set, and forming an inductive circuit for predetermined currents between the antenna and ground.

In testimony whereof I afiix my signature.

JEFFERSON s. PALMER. 

